Process and apparatus for annealing glass



Jan. 21,` 1930, E. TFERNGREN PROCESS A ND APPARATUS FOR ANNEALING GLASS Filed Jan. 2, 192e -mqWh qreh.

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yINYE NT DE.' Enoch 7T Fern AT T DENEK ldatented Jian.. l, lglll @NOCH T. FIERNGREN,

Application filed January 2, 1926. Serial No. 78,772.

The present invention relates to an improved process and apparatus for annealing sheet glass.

An important object of the invention is to provide an annealing oven or leer with vmeans whereby a less turbulent atmosphere may be maintained within the oven.

Another object of the invention is tocreate within a confined heated atmosphere a mediuln having a sustained temperature condition which gradually decreases throughout its length, and which is substantially uniform throughout its width.

A further object of the invention is to create within an annealing oven and around the glass passing'therethrough a condition which is capable of protecting the glass from intercourse with elements having objectionable temperatures.

Other objects and advantagesofthe invention will become apparent during the course of the following description.

In the drawings whereby like numerals are employed to designate like parts through out the same,

Fig. 1 is a longitudinal sectional elevation of the improved annealing oven,

Fig. 2 is a transverse section through a hot portion of the oven taken substantially on :o line 2-2 in Fig. l,

Fig. 3 is -a fragmentary transverse section through a cooler portion of the oven taken substantially on line 3-3 of Fig. 1.

Referring to the drawings in detail, the numeral 4 refers to a chamber in which the sheet of glass 5 is continuously drawn and flattened in a manner more fully disclosed in a patent to Colburn 1,248,809, granted Dec. 4 1917.

7In front of and attached to the chamber 4 in horizontal alignment With the Isheet as it passes therefrom is an oven or leer 6 of suitable size for annealing the sheet. The sheet 5 is preferably advanced through the leer upon and by a plurality o f driven rolls 7.

There are, openings 8 provided in the side walls of the leer -for either removing or replacing the rolls 7 Unless these openings are suitably closed or sealed, unequal heat losses will result therefrom which may prove undrawings.

desirable-toward proper annealing of the sheet. By inserting plugs 9 of suitable in sul'ationj within the openings 8 these heat losses will be somewhat neutralized.

The leer is preferably heated by means of burners 10 suitably spaced longitudinally thereof. As set forth in my copending application, Serial No. 75,270, filed Dec. 14, 1925, means are provided for suitably insulating the leer in order to maintain a more uniform temperature transversely therein.

In conjunction with this feature it is the fundamental purpose of the present inventionto create and maintain longitudinally of the leer and around the glass sheet passing therethrough a condition which is capable of protecting the sheet from any luctuatingtemperatures which might interfere with the proper annealing of the glass.

rlhe leer improvements covered by` this invention are not necessarily limited to the sheet glass apparatus illustrated in the drawing, but are applicable to most any type of annealing leer.

A preferable leer construction for the purpose of meeting the requirements of the pres-l ent invention-is shown in the accompanying The side walls 11 of the leer are provided with a plurality of vents 12 having flues 13 communicating therewith. The effectiveness of the flues 13 is controlled by dampers 14 provided therein. It will be noticed that the vents 12 are spaced longitudinally of the leer at spaced intervals and that their vertical distances from the line' of travel of the sheet gradually decreases until the last few are approximately in line with the sheet. The ceiling at the end of the leer beyond the side wall vents 12 is providedwith a plurality of vents 15. These vents are arranged in staggered groups in open communication with conduits 16 and 17, also in the leer ceiling, each conduit leading to its Irespective flue 18 or 19. Dampers 2O are provided within the lues 18 and 19 for controlling the draft created by them.

It is believed thatwith-a leer constructed in accordance with the present invention, a very satisfactory annealing condition can be attained. It isa well-known fact inthe art y OF TOLEDO, OIUO, ASSIGNOR T0 LIBBEY-OWENS GIl'aASSy COMANY, l OF TOLEDO, OHIO, A CORPORATION OF OHIO sure is comparatively high at one end of the leer and which gradually approaches atmosplieric temperature and pressure at the other end offthe leer. This medium is continuously maintained by withdrawing heat from the" leer at different levels through the side wall vents 12. The amount of heat withdrawn at different points along the leer is controlled by the use of the dampers `14 in the llues 13. In order that theglass sheet may gradually be subjected to atmospheric pressure and temperature, (there being a pressure greater than atmospheric pressure in the leer due to the resence of the high temperatures therein) t e medium surrounding the glass gradually vanishes by being gradually drawn through the vents 15 in the far end of the leer ceiling. The rapidity with which the medium is caused to vanish is controlled by the use of the dampers 20. l The glass sheet during its advancement through the annealing vmedium whose temperature has been gradually and systematically reduced, it is to be understood, has also been protected from stray fluctuating temperatures which prevail within the ordinary leer, :these fluctuating temperatures often causin considerable breakage.

In t e ordinary annealing leer the temperature therein is reduced byv gradually reducing the number of burners in the leer and. also by reducing the gas supply vto the burners at the colder portion of the leer. The gases and heat are removed from this type of leer through a single flue usually placed somewhere along the leer ceiling. The Idraft created by this ilue it is appare'nhcauses a very undesirable condition inthe leer, creating a plurality of air currents of varying temperatures to sweep from all directions toward the flue across the glass sheet.'

The improvements covered by the present invention eliminate the objectionable features of a. single ceiling flue, for as the temperature of the annealing medium is lowered, gases and-heat pass from the leer at a plurality of points corresponding yto the location yof each reduction intemperature of saidv medium.

. Another advantage of the present invention resides in the fact that the leer rolls which are enclosed within theabove-mentioned medium therefore will have approximately the same temperature as said medium, and thus Vin a horizontally movin phere along a portion of the leer, sealing means for 4preventing draft currents of local character at the level of sheet, and means for causing local escape movement of heated atmosphere at dierent levels below the sheet.

2. In a leerfor annealing and cooling a4 g5 continuous glass sheet, roller means for moving the sheet therethrou h, means for releasing supplemental heat into the atmosphere along a portion of the leer, sealing means for preventing draft currents of local character at the transit level of sheet, and means for causing local escape movement of heated atmosphere at diierent levels below the sheet in that portion of leer where heat is released,

and for drawing ol the heated atmosphere at the series of exits checkerboarded above the level of sheet at the cooling end of leer.

3. A sheet glass annealing oven for receiving a horizontally moving sheet, including side walls and a ceiling, said walls being provided at longitudinally spaced locations with vents arranged in dill'erent horizontal planes beneaththe sheet.

4. A sheet glass annealing oven for receiving a horizontally moving sheet, including the vents to the line of travel of the sheet gradually decreasing from the hot to the cold end of the oven.

' 5. .A sheet glass annealing oven for receiv- I sheet, including si e walls and a ceiling, sald provided at longitudinally spaced locations with vents arranged in different horizontal planes beneath the sheet, and dampers l for controlling ,said vents.

6. A sheet'glass annealing oven for receiv- 12o ing ay horizontally moving sheet, including side walls and a ceiling, saidside Walls being provided at longitudinally spaced locations with vents arranged in different horizontal planes beneath the sheet, and the ceiling being 125 also provided with a plurality of vents at the end of the oven beyond the side wall vents.

7. A sheet glass annealing oven for receiving a horizontally moving sheet, including side walls and a ceiling, said side walls being 12J side walls being provided at longitudinally spaced locations with vents arranged in dierent horizontal .planes beneath the sheetfthe vertical distances from the vents to the line of travel of the sheet gradually decreasing from the hot to the cold end of the oven, and the ceiling being also provided with a plurality of vents at the cold end ofthe oven beyond the side wall vents. 8. ln a sheet glass annealing oven, means for supporting the sheet horizontally, means within the oven for heating' the same, and means in the side walls of the oven at different horizontal planes beneath the sheet for withdrawing heat therefrom.

9. In a sheet glass annealing oven, means for supporting the sheet horizontally, means for introducing heat within the loven at4 spaced locations longitudinally thereof, and means in' the side walls ofthe oven at diffrent horizontal 'planes beneath the sheet for withdrawing heat therefrom, the vertical distances vfrom the last named means to the'line' `of travel of the she'et gradually decreasing i which consists inpassing from the hot to the cold end of lthe oven.

'1.0. ln a sheet glass annealing oven, means for supporting the sheet yhorizontally therein, means for introducing heat within the oven at spaced locations longitudinally thereof, means in the side walls ent horizontal planes beneath the withdrawing heat therefrom, 'and means in the vceiling of the oven at one end thereof beyond the second named means for also withdrawing heat therefrom.

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of the oven at differsheet" for for supporting the sheet therein, means for i heating said oven, and means in the side walls of the oven arranged in different horizontal planes for withdrawing heat therefrom.

16. A sheet glass annealingovenl for receiving a substantially horizontally moving sheet including a bottom, side walls, and a ceiling, said side walls being provided at longitudinally spaced locations with vents arranged in different horizontal planes.

17,. A sheet glass annealing oven for rcceiving a substantially horizontally moving sheet including a bottom, sidewalls, and a ceiling, said sidewalls being provided at longitudinally spaced locations with vents arranged in different horizontal planes, and the ceiling being also provided with a plurality of vents at the end of the oven beyon'dthe side wall vents. v

Signed'at Toledo, in the county of Lucas, and State of Ghio, this 31st day of,` Dece`mber, 1925. i 'ENOCH T. FAERNGREN.

ll. The process of annealing sheet glass the sheet longitudiv y nally through a confined heated atmosphere,

and gradually decreasing the temperature of' the sheet by drawing o" heat at spaced intervals and at different horizontal 'levels beneath said sheet.

12: The process of annealing sheet glass which consists in passing thelsheet horizontally through-an annealing oven,'introducing heat into the oven'at spaced locations longitudially thereof, and graduallydecreasing the temperature of the sheetby drawing 01T.

' heat at spaced intervals and at different horizontal levels beneath the sheet and in also drawing off heat from above the sheet.

13. The process of annealing sheet glassv which consists in passing the sheet `through a confined heated atmosphere, and gradually decreasing the temperature of the sheet by drawing oit heat at spaced intervals and at different horizontal levels.l

14. The process of annealing sheet glass which consists in passing the sheet in' a generally horizontal direction through a congradually dedifferent horizontal` levels. V15. In a'sheet glass annealing oven, means 

